Safety coupling



L. C. HlsEYl SAFETY COUPLING Filed oct 6. 1924 Oct. 26 1926.

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Patented Oct. 26, 1926.

UNITED STATES LYMAN C. HISEY, OF LOS ANGELES, CALIFORNIA.

SAFETY COUZPLING.

Application led October 6, 1924. Seral No. 741,908.

This invention relates to safety devices to be used in connection with drilling oil wells and pertains more particularly to a safety coupling for drill pipe and the like.

The principal object of this invention is to reduce or to practically eliminate the loss of time caused by'so-called twist-offs.

It will be understood, in consideration of this inventiom that a twist-off, practically speaking, iscaused by parting of the drill pipe, and the result is that that part of the drill pipe below the point'of parting cannot be withdrawn from the hole except by the application of fishing tools. The usual time lost is that required for the removal of the upper portion of the drill pipe andthe successive attempts to fish out the said lost portions. Y

In the great majority of cases, drill pipe will part at or adjacent to the lower threadm ed portion of the pipe section where it screws onto a tool joint. It is a particular object of this invention to provide means whereby those portions of the drill pipe bclow the twist-off may be removed'along with the portions above the'twist-off.

Another object of the invention is to pro-- vide a comparatively inexpensive safety coupling so that any operator can afford to install one at each and every tool joint throughout the string of pipe so that no matter where a twist-off occurs the entire string of pipe may be removed as readily as though no twist-off had occurred.

Still another object of the invention is j to provide a device of the character described which will not come into operation until an attempt is made to actually raise the pipe.

A further object which will not be affected should the drill pipe continue to rotate for any appreciable springs 26. Tlie'friction member is shown time after the twist-off occurs.

Still other objects and advantages ywill appear hereinafter. y t

I have illustrated by `the accompanying drawings one practical embodiment of my invention. Y

In the said drawings, Figure 1 is a view in vertical section of the said embodiment as applied to a tool joint and adjacent sections of drillpipe;

Figure 2 is a view in section thereofV seen j o n the line 2-2 of Figure 1';

of the invention toi provide a device of the character described i Figure 3 is a view in section seen on the line 33 of Figure 1;k

-Figure 4L is a view in vertical section similar to that of Figure 1, showing the device in operation; Figure 5 is a view in vertical section of a part of the device hereinafter knownas the friction means,`

as it appears in normal expanded position apart from the drill pipe. More specifically, 7 and 8, respectively, indicate sections of drill pipe which are connected to each other by tool joint members 9 and 10, suoli arrangement of pipe sections and tool joints being that most commonly employed. In carrying out my invention, section 10 of the tool .joint is internally threadedas at 1l to receive the improved safety coupling which will now be described.

The coupling includes Va mandrel '12 of tubular form to provide abore or fluid course 14, sothat circulation through the bore `of the drill pipe is not interfered with. i Y

The mandrel is provided with elongated apertures, such as 16, to allow mud to easily venter or leave the bore of the mandrel and to prevent clogging of thel ends thereof. Said mandrel is externally threaded at the lower. end, as at 18, sof that it may be attached to the `corresponding section of the tool joint. It is found fromexperience that in about.80% of the twistloffs the pipe parts 1 at` about the oiiit Uenerall indicate b the numeral 2(l b l d y My improved coupling further includes a friction member 21 arranged to frictionally engage the inner margin 22 of the upset end of the drill pipe. In theembodimentillusytrated, saidl friction member is composed of spaced rings 24 and 25 which are a loose sliding fit upon the mandrel and which are connected by a plurality of bowed flat in Figure as it appears when allowed to assume normal shape. When a drill pipe or tubing section is forced over this friction member, particularly when the friction v member is in position `over the mandrel, the

parts will assume the position shown in Figure 1 and the springs will frictionally engage -tlie inner margins of the pipe over which it `is fitted. The upper end of the mandrel is externally tapered as at 27, se

`thatit increases in diameter upwardly.

A plurality of slips 29l are provided which are equally spaced circumferentiallyV about the tapered part of the mandrel. Said slips are held in sliding engagement with the tapered surface by meansof a iiat'springmember 30 which comprises about one and one-half or more convolutions. l/Vliens'aid spring is formed and tempered, Vits normal diameter is slightly less than the diameter which it assumes when it is caused to encompass the assembly of the slips. andthe mandrel.

(bviously, if the slips and the spring are forced upward as a unit along the tapered surface, the outer toothed surfaces 3l of the said slips will be gradually moved toward the inner margin of the pipe, and the assembly of slips and coil spring will increase in effective circumference. V

In taling advantage of my invention, in the operation or in the use of drill pipe, tubing and the like, the complete device, including mandrel, slips and friction member, should be installed as shown in Figure l, at each tool joint. To install the safety coupling, it is. only necessary to screw the mandrel with the attached friction means and slips to the upper tool joint member..

To attach the tool joint member to the pipe fsection, it is only 'necessary to force the friction means and mandrel into the open end` of thepipe before the actual operation of securing the tool joint to that end .ofthe pipe is accomplished. Oncethe'tool joint.

member is so attachedV to. the pipe, such operation -doesnot have to berepeated, and

in disconnecting stands of pipe at the tool joints thepcouplings arenot interfered. with.

\ orexposed; In fact, .my improved safety the well. The couplings once installed-may be left in place indefinitely and require' no attent-ion nor inspection.

Assuming that a twist-olf occurs at any point between the upper section of the tool joint and that part ofthe pipewall whichy is engagedby thefriction member, the operation of the device will be as follows. Should the pipe part at such. point, that portion ofthe drill. pipe above the 'point of' twist-off will probably'continue to rotate or be rotated Vuntil suchtime as the driller becomes aware of the twist-off and brings'theVV rotating means to a stop. During such unnecessary rotation of the drill pipe, `the friction means with its collars is quite free to' revolve upon a mandrel and lproduces no effect whatsoever in so far as operationof the'device `1s concerned.

Due to the suddenlyy decreased load or torque, ,the Vdriller is awarethat a twist-off has occurred, and after. havingjstopped ythe rotatingmeans may start to hoist thepipe.VV

Now, when the pipe is being hoisted that portion below the twist-off will tend to remain stationary in the bore of the well. Therefore, it may be said that the pipe above the twist-off, together with the fricplurality of slipsare jointly moved upward along the mandrel-.by virtue of the frictional engagement of the springs vwith the inner margin of the pipe. By the time the slips have been so moved a few inches, their toothed outerV surfaces will be brought into contact with the inner margins of the wall and will. effectively engageV same, whereupon there is a tendency for the slips to be moved even further upward. Therefore, immediate-ly after the toothed surfaces come in contact with said margins, a combined frictional engagement and wedging action will be setup between such ksurfaces and margins, and. that portion of the drill pipe above the twist-off will becomeV most effectively attached indirectly to the mandrel.

It will be apparent, now, that as the pipe above the. twist-off is hoisted, all portions of the .pipe below lthe twist-olf will be hoisted, the mandrelV acting as the connecting link. Therefore, by installing my improved safety coupling in each tool'joint, the only delay that will be occasioned by atwist-olf'is the time required to hoist the pipe, replace the broken sectionsand again lower the entire string into the hole.. Should the twisto'occur at or near the time when a change ofdeitsfis contemplated, no appreciable loss offtime will be experienced.

While I. have shown and described a specific embodiment of my invention, I do notlimitmyselfvto any specific construction or arrangement of parts, and may alte'rr'the construction and arrangement of parts as occasion may require without enlarging the kscope of the invention within the appended claims. i

l claimas my invention:

1. In combination, pipe sections, a joint connecting said sections, a mandrel carried bysaid` joint and extending into the interior of one 'pipe section', and expanding means carried bysaid mandrel arranged to expand and connect with the pipe should said pipe. move relative to said joint.

2. In combination, pipe sections, a joint connecting said sections, a mandrel carried by said joint and extending into the interior of one pipe section, and expanding means carried by said mandrel arranged to expand and v engage said pipe internally should saidpipe move relative to said joint.

3. In combination, expanding pipe engag.,H ing means adaptedto engage theinner margin of a pipe should the pipe be moved in a given direction relative to said means, and

'a tool joint to which the pipe and pipe engaging means may be each secured with the said means internally of the pipe.

4f. In combination, a pipe, a tool joint carried by said pipe, a mandrel carried by said tool joint and extending into the bore of said pipe, expanding means carried by said mandrel for engaging the inner surface of the pipe in event said pipe is moved longitudinally and relative to said joint and means carried by said mandrel rictionally engaging the inside of the pipe constantly and operative to expand said means upon such movement.

5. In a device of the character described, a mandrel having a portion of increasing diameter upwardly, pipe engaging slips assembled around said mandrel and movable.

along the mandrel vertically, a collar loosely encompassing said mandrel below the slips,

and friction means frictionally engaging said pipe internally, said means arranged to move said collar with itself.

6. In combination, a pipe, a tool joint at the lower end of the pipe, a mandrel car, ried by said joint and extending upwardly into the bore of said pipe, and wedging means carried between said mandrel and pipe arranged to connect the mandrel to the pipe when the latter moves upwardly relative to the former.

7. In combination, a pipe, a coupling screw threaded to one end of said pipe, a mandrel attached to said coupling and extending into said pipe, expanding pipe engaging means carried by said mandrel, and means frictionally connecting said pipe and said pipe engaging means whereby said expanding means is caused to expand after a predetermined dlongitidinal movement of said i e to sai coup ino'. e

p p LYMAN o. I-nsEY. 

